Ernst kassner



Aug. 7, 192s.

E. KAssNER RESETTING MECHANI SM Filed Jima 1a, 192e lKVi NTOR:

Patented -Aug. 47, 1928.

PATENT OFFICE.

ERNST KASSNER, OF BERLIN, GERMANY.

BESETTIN G MECHANISM.

Application filed June 18, 1926, Serial No. 116,770, and in Germany .April 17, 1926.

This invention relates in general to calculating machines and the like and more particularly to resetting mechanism.

In calculating machines of all kinds, particularly in cash registers, adding machines,

permitted between moving parts as in the pivots of wheels, pawls, etc. is such that in a complete revolution ol the shaft that carries the number wheels inaccuracies amounting to as much as will occur; In addition to this7 in rapid working, when the peripheral speed is very high, considerable centrifugal and kinetic forces arise which have to be eliminated quickly and therefore tend to increase the inaccuracies of the restoring operation. Due to these causes it may -happen that one or more of the number Wheels, instead of iying back to normal or Zero, will move to the next number, i. e. 9, thereby giving rise to errors in the subsequent calculating operations. Such wrong settings are particularly7 liable to occur in cash registers of the type in which the restoration to zero is effected in the last part of the turn of the crank when the calculat-ingoperation itself has been completed, so that only a small angular movement of the crank remains for the restoration of the parts to zero and the restoring operation therefore has to be effected at a very high speed.

The object of the present invention is to remove this disadvantage. This is accomplished by arranging the shaft that carries the number wheels to be rotated positively beyond its zero position when the parts are restored to normal and to be substantially positively turned back at about the same speed to Zero. After the excess rotation, i. e. rotation of the shaft beyond its zero position, the inaccuracies in the gear, which are bound to exist on account of the necessary play between interengaging parts or wheels and which sum up in the direction of their rotation, are counter-balanced or eliminated during the said rapid backward rotation of the shaft to such an extent that all parts reach their exact zero position. The positive backward rotation gives rise to frictional forces that oppose the kinetic forces and are of such magnitude as to completely destro the latter, so that the number Wheels, Whic are held by tensioned arresting springs, yield to the action of these springs and go into their zero positions. By this means additional stopping members are rendered unnecessary.

'Ihe invention is illustrated by Way of eX- ample in the drawings, Figs. 1, 2 and 3, which show a number-Wheel of a calculating machine and restoring mechanism associated therewith in three different positions.

Mounted on the shaft a, so as to rotate relatively thereto are number-Wheels as b.

To perform calculating operations the number-wheels can vbe turned into any desired position by means of toothed gear Wheels c, d, indicated by dash and dot lines in F ig. 2. For the restoration of the parts to zero a second shaft e is provided that extends parallel to the shaft a. Mounted on the shaft e and fixed relatively thereto is a toothed member or sector f, which is adapted to mesh with the toothed member or wheel g that is xed on the shaft a. This shaft has a groove or notch it adapted to engage with a number-wheel restoring member in the shape of a pawl c that is pivotally mounted in the number-wheel. The pawl 7c is held in engagement with the notch h by a spring i. During calculating operations the number wheels revolve in the direction indicated by the arrow and the pawl glides over the periphery of the shaft a, but when the parts are restored to zero, which is effected by rotation of the restoring shaft e, the number- Wheel shaft a is turned, this rotation being also in the direction of'the arrow and resulting inv the rotation of the number-Wheels by means of the pawl lc. Before the commencement and after the completion of -thls restoring movement the shaft a is locked against rotation by a locking means compris.

ing a primary locking member orl locking disc Z xed on the shaft a and having a curved recess m and a secondary locking member or disc n which is fixed relatively to the toothed sector f. When the curved periphery of the disc n enters the curved recess m the shaft a is, as already stated, locked against rotation.

In the last part of the restoring revolution of the shaft a, (which may be effected by the toothed members f and g, as will be presently set forth, to restore the number- Wheels,) a means for preventing false setwhich will now be described. FiXed to the` tings of the wheels comes into bperation disc Z of the shaft a is a primary cam p that cooperates with a secondary cam o attached to the disc n. During the last part of the restoring movement and-in the case of restoring gears that are provided with toothed restoring members as shown in the :drawing-before the last tooth ofthe toothed sector f becomes disengaged fromV the toothed wheel g, the two cams o and' p con-V and 3. As soon as the shaft a has been turned to the utmost limit beyond its zero position, further rotation of the restoring shaft e, and the resulting cooperation of its cams 0 and p, and of the parts or other cam surfaces g and 7', causes the disc Z and number-wheel shaft a to be rotated backward at about the same speed, the projection p of the cam on the disc Z sliding backwardsat this juncture on the cam o. Fig. 3 shows the parts almost in their zero position and Fig. 1 shows them after the zero position is reached. In this position the curved recess m of the primary locking member is in engagement with the curved periphery of the secondary locking member n and locks the shaft a, and hence the number-wheels, precisely in their zero position.

An important feature of this novel mechanism for preventing inaccurate restoration to zero is that in the last part of the restoring movement the parts to be restored are positively moved by cams beyond their zero position and then back again at approximately the same speed to the proper Zero position, whereby the eects of the necessary play between moving parts and of their momentum are eliminated and the parts are made to go into their precise zero positions.

1. In a machine of the kind described, having number wheels, and means for turning the number wheels into any desired positions, a restoring member for turning the wheels into their zero positions, and means for positively moving the restoring member in one direction through a predetermined angle beyond its normal position during its restoring operation and means for thereupon rigidly engaging it and positively moving it in the opposite direction back into its normal positlon.

2. In a machine of the kind described,

wheels into` their zero positions, and means 'for positively moving the restoring member in one direction beyond its normal position during its restoring` operation and for thereupon positively moving it at practically the same speed `in the opposite directionV back into its normal position, said last mentioned means for moving the restoring member being shaped to positively control the speed of rotation of the restoring member as it passes its normal position in either direction of rotation.4

3. In a machine of the kind described, having a shaft, number wheels revolubly mounted on said shaft, and means for turning the number wheels on said shaft into any desired positions, a primary toothed member fixed on the shaft, a secondary toothed member adapted to intermittently engage the primary toothed member to' rotate said shaft, connecting means between the shaft and the number-wheels for restoring the number wheels to their Zero positions when the shaft is turned, cooperating means associated respectively with the shaft and the secondary toothed member for turning the shaft beyond its zero position, another cooperating means associated respectively with the shaft and secondary toothed member for subsequently turning vit back to its zero position.

4. In a machine of the kind described, having a shaft, number wheels revolubly mounted on said shaft, and Ymeans for turning the number wheels on said shaft into any. desired positions, a primary toothed member fixed on the shaft, a secondary toothed member adapted to intermittentlyv engage ythe primary toothed member to rotate said shaft, connec-ting means between theshaft and the number-wheels for restoring the number wheels to their zero positions when the shaft is turnedgtwo cooperating cams, one fixed relatively to the shaft and one fixed relatively tothe secondary toothed member, for turning the shaft beyond its zero position, and cam surfaces asso-- ciated with the shaft and secondary toothed member for turning the shaft back into its zero position.

5. In a machine of the kind described, having a shaft, number wheels revolubly mounted on said shaft and means for turning the number wheels on said shaft into any desired positions, a primary toothed member fixed o-n the sha-ft, a secondary toothed .member adapted to intermittently engage the primary toothed member to-rotate said shaft, connecting mea-ns between the shaft and the number-wheels for restoring the number wheels to their zero positions when the shaft is turned in one direction, two cooperating cams, one fixed relatively to the shaft and one fixed relatively to the secondar toothed member, for turning the shaft eyond its zero position, and cam surfaces associated with the shaft and secondary toothed member for turning it back into its zero position said cams being arranged to become operative during the rotation of said shaft in said direction shortlyy before it reaches its zeroposition.

6. 1n a machine of the kind described, having a shaft, number wheels revolubly mounted on said shaft, and means for t-urning the number wheels on said shaft into any desired positions, a primary toothed member fixed on the shaft, a. secondary toothed member adapted to intermittently engage the primary toothed member to rotate said shaft, connecting means between r the shaft and the'number-whcels for restoring the number wheels to their zero position when the shaft is turned in one direction, locking means for locking the shaft against rotation during the turning of the lnumber wlieelsinto any desired ositon, cooperating canis associated with tlie shaft and the secondary toothed member for turning the shaft beyond its zero position when it is rotated and for subsequently turning it back to its zero position.

7. In a machine of the kind described, having a shaft, number wheels revolubly mounted on said shaft, and means for turnlsaid sha ing the number wheels on said shaft into any desired positions, a primary toothed member fixed on the shaft, a secondary toothed'member that transitorily cooperates with the primary toothed member to rotate t, connecting means between the shaft and the number-wheels for restoring the number wheels to their zero position when the shaft is turned in one direction, a primarylocking member fixed to said shaft and provided with a curved recess, a secondary locking member fixed relatively to the secondary toothed member and having a curved peripheral surface adapted to enter said curved recess for preventing movement of the shaft relatively to the secondary locking member and being provided with a rectilinear surface forming a chord between two points of said curved peripheral surface, and two coo rating cams, one fixed relatively to the s aft and one fixed relatively to the secondary toothed member, for turning the shaft beyond its zero position, the surface of said primary locking member at one end of its said curved recess being adapted to subsequently engage said rectilinear surface to turn the shaft to zero position.

In testimony whereof I have signed my name to this specification.

ERNST KASSNER. 

